Fasinumab may improve pain and function in patients with osteoarthritis (OA) pain, including patients who previously had an inadequate response to analgesics, according to phase 2b/3 placebo-controlled randomized trial results published in Arthritis & Rheumatology.

The study included participants with moderate to severe knee or hip OA pain with a history of inadequate response or intolerance to analgesics who were randomly assigned to receive fasinumab at 1 mg, 3 mg, 6 mg, 9 mg, or placebo every 4 weeks for 16 weeks. Study participants were followed for 36 weeks.

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The study’s efficacy end points were changes from baseline at week 16 in Western Ontario and McMaster Universities Osteoarthritis Index pain and physical function subscale scores and in Patient Global Assessment (PGA). Joints were monitored during treatment and follow-up using scheduled assessments of plain film and magnetic resonance imaging. Of the 421 participants initially enrolled, 342 completed the study.

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Patients treated with fasinumab at any dose vs placebo reported statistically significant and clinically important reductions in pain (least square mean difference, −0.78 to −1.40). No dose-dependence of the effect of fasinumab on pain was detected. Patients treated with any of the 4 doses of fasinumab vs placebo indicated reduced PGA scores, with statistically significant reductions in participants treated with fasinumab at 1 mg and 9 mg (>30% improvement, P=.0132 and P=.008, respectively).

The rate of treatment-emergent adverse events was 17% for fasinumab and 10% for placebo. In the fasinumab groups, 4% of participants discontinued treatment due to adverse events compared with 1% of patients receiving placebo.

Arthropathies occurred in 7% and 1% of participants treated with fasinumab and placebo, respectively (25 in total), and were found to occur in a dose-dependent manner, with 2 and 10 arthropathies reported by patients treated with fasinumab at the lowest and highest doses, respectively.

“The observation that efficacy at lower doses was similar to that of higher doses, but with lower rates of arthropathy, demands that future studies explore the benefit-risk at these lower doses,” the researchers noted.


This study was sponsored by Regeneron Pharmaceuticals, Inc.


Dakin P, DiMartino SJ, Gao H, et al. The efficacy, tolerability and joint safety of fasinumab in osteoarthritis pain: a phase IIb/III double-blind, placebo-controlled, randomized clinical trial. [published online June 17, 2019]. Arthritis Rheumatol. doi:10.1002/art.41012

This article originally appeared on Clinical Pain Advisor